. . . . . . . . . "Papilio glaucus" . . "Silphium perfoliatum" . . "Barbara Charlton. 2017. Papilio glaucus associated species with names lookup Silphium perfoliatum. iNaturalist.org. Accessed at <https://www.inaturalist.org/observations/7569929> on 05 Apr 2018." . . . . "http://iNaturalist.org is a place where you can record what you see in nature, meet other nature lovers, and learn about the natural world." .